This invention relates to a device for locking the throttle control of a diesel engine so as to maintain that engine at a fixed rpm for a period of time under control of the driver.
Diesel engines can only operate effectively and without damage if they are properly warmed up prior to use of the vehicle within which they are mounted. Contrary to the conventional gasoline engine, diesel engines do not include a choke control, which can be used during the starting process and to increase the idle speed of the engine during the warming-up process.
The normal idle speed of the diesel engine is generally not sufficient to properly warm up the engine and of course drivers are very reluctant to sit holding the conventional foot operated lever at a slightly open position to speed up the engine while it is warming.
Devices have therefore previously been proposed for locking the throttle in a slightly open position so that the engine can run at an increased speed of for example 1,500 rpm for a period of time to achieve proper warmup without the necessity for the driver being present to control the throttle position.
The foot operated lever within the cab or driver compartment communicates through a linkage generally in the form of a rod which moves longitudinally to directly operate upon a lever of the fuel pump. The generally available locking device comprises a cable operable by a pull knob inside the cab or driver compartment which directly pulls upon the lever to the fuel pump. These cable devices have been found to be unsatisfactory in that they are prone to failure and are difficult to adjust to the required rpm. They are therefore unpopular with the operators and are generally not supplied by original equipment manufacturers. Thus, in most cases, they are a subsequent addition to the equipment without proper location for the connection between the cable and the lever thus further reducing the effectiveness of the product.
Various devices have been available in the prior art for use as governors of a diesel engine which operate to vary the fuel pump lever in dependence upon various outside conditions. These are of course expensive and have properties completely unsuitable for the simple requirement with the present invention is concerned, that is, the locking of the fuel pump at or approximately at a required position to run the engine at a slightly increased rate for a period of time until deactuated by the operator.
It is one object of the present invention, therefore, to provide an improved device for controlling the rate of revolution of a diesel engine which is inexpensive to manufacture, efficient in operation and with few wearing parts thus giving long life.
According to the first aspect of the invention therefore is provided a device for controlling the rate of revolution of a diesel engine of a vehicle of the type including an engine compartment within which the diesel engine is mounted, a driver compartment separate from the engine compartment, a fuel flow throttle control device mounted within the engine compartment for varying the amount of fuel fed to the engine so as to vary the rate of revolution thereof, a foot actuable lever mounted within the driver compartment movable to varying positions between a maximum and a minimum position and a linkage communicating movement of the lever to the throttle control device, said device comprising a bracket having a plate member with holes therein for bolting of the plate member to a wall of the engine compartment and a support portion upstanding from the plate member, means defining an opening through the support portion for receiving said rod of said linkage passing therethrough in longitudinal movement thereof, a lever pivotally mounted on said support portion about a transverse axis arranged closer to one end of the lever than to an opposed end thereof, an air actuable cylinder having one end attached to said support portion and an opposed end attached to said opposed end of said lever such that supply of air to said cylinder causes movement of said lever about said pivot axis, said one end of said lever being arranged relative to said opening so as to engage said rod passing therethrough to clamp said rod, and a switch separate from said bracket and having means thereon for mounting of said switch on a wall of said driver compartment, said switch including means for selectively controlling the supply of air to said cylinder.
According to a second aspect of the invention, there is provided a vehicle including a diesel drive engine, an engine compartment within which the engine is mounted, a driver compartment separate from the engine compartment, a fuel flow throttle control device mounted within the engine compartment for varying the amount of fuel fed to the engine so as to vary the rate of revolution thereof, a foot actuable lever mounted within the driver compartment movable to varying positions between a maximum and a minimum position, a linkage communicating movement of the lever to the throttle control device, a clamp member mounted within the engine compartment and arranged to be movable from a first position free from said linkage in which said linkage can freely communicate said movement to a second position in which it clamps against movement said linkage in a position thereof according to the position between the maximum and minimum of the lever, actuating means for moving said clamp member between the first and second positions and a switch mounted within said driver compartment for selectively supplying power to said actuating means.
Contrary to the conventional device which comprises a cable which operates in parallel to the throttle control linkage, the present device operates to clamp the existing throttle control linkage at a position along its length so as to hold the linkage in the required position. The operator therefore instead of trying to control the rate of revolution of the engine by pulling on a cable, simply acts to press the foot throttle lever to the required location to obtain the desired rpm and the operates the switch which immediately clamps the throttle linkage in that location, holding it until the switch is reverted to its first position thus releasing the air from the cylinder.
A specific design provided by the upstanding support brackets as a pair of plate members pivotally mounting the lever and the actuating cylinder therebetween so as to clamp the linkage rod between the lever and the openings through the plate member is a particularly simple and effective technique for providing the clamping mechanism in a device which can be cheaply manufactured and simply mounted within the engine compartment.
With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the best mode known to the applicant and of the preferred typical embodiment of the principles of the present invention, in which: